The present disclosure relates to a paper feed device and a paper feed method.
Conventionally, as a paper feed cassette incorporated in an image forming apparatus such as a copy machine, a printer, or the like, there is known a paper feed cassette having a paper sheet housing case that is open upward and a paper sheet stacking plate that is configured to be movable in an up-down direction in said paper sheet housing case. On an upper surface of the paper sheet stacking plate, a batch of paper sheets are placed in a state of being stacked. The paper sheet stacking plate is linked to a motor via wire. By a driving force of the motor, the paper sheet stacking plate is caused to ascend as the number of paper sheets decreases so that an uppermost one of paper sheets placed on the paper sheet stacking plate is always positioned at a paper feed position. At this paper feed position, a pick-up roller is provided by which an uppermost one of paper sheets in a paper sheet batch is separated from the paper sheet batch to be fed to a paper sheet conveying path.
The above-described conventional paper feed device, however, presents a problem that at the time of paper sheet changing by a user, in a case where the number of paper sheets remaining on the paper sheet stacking plate is low, compared with a case where a sufficient number of paper sheets are remaining there, it is hard for the user to insert his/her finger(s) between a lowermost one of the paper sheets and the paper sheet stacking plate and thus to grasp the paper sheets. The above-described paper feed device, therefore, is susceptible to improvement from the standpoint of facilitating a paper sheet changing procedure by a user.
A paper feed device according to one aspect of the present disclosure includes a paper sheet housing case, a paper sheet stacking plate, and a lift-up mechanism. The paper sheet housing case is open upward. The paper sheet stacking plate is provided in the paper sheet housing case in such a manner as to be movable in an up-down direction, and on an upper surface thereof, a batch of paper sheets are placed in a state of being stacked in the up-down direction. The lift-up mechanism causes said paper sheet stacking plate to ascend as the number of the paper sheets on the paper sheet stacking plate decreases so that an uppermost one of the paper sheets in the paper sheet batch on said paper sheet stacking plate is positioned at a prescribed paper feed height.
The above-described paper feed device further includes a push-up member for pushing up from below a paper sheet batch on the paper sheet stacking plate and a push-up member driving device that, in a case where the number of paper sheets in the paper sheet batch on the paper sheet stacking plate is higher than a prescribed number, causes the push-up member to be positioned not higher than the upper surface of the paper sheet stacking plate, and in a case where the number of paper sheets in the paper sheet batch on the paper sheet stacking plate is not higher than the prescribed number, makes at least a part of the push-up member protrude upward beyond the upper surface of the paper sheet stacking plate so that a part of a lower surface of a lowermost one of the paper sheets in the paper sheet batch placed on the paper sheet stacking plate is pushed up from below by said push-up member, thereby creating a clearance between the lower surface of the lowermost one of the paper sheets and the upper surface of the paper sheet stacking plate.
A paper feed method according to one aspect of the present disclosure is a paper feed method for the paper feed device having the configuration, in which via the push-up member and push-up member driving device, in a case where the number of paper sheets in a paper sheet batch on the paper sheet stacking plate is higher than a prescribed number, the above-described push-up member is caused to be positioned not higher than the upper surface of the paper sheet stacking plate, and in a case where the number of paper sheets in the paper sheet batch on the paper sheet stacking plate is not higher than the prescribed number, at least a part of the push-up member is made to protrude upward beyond the upper surface of the paper sheet stacking plate so that a part of a lower surface of a lowermost one of the paper sheets in the paper sheet batch placed on the paper sheet stacking plate is pushed up from below by the push-up member, thereby creating a clearance between the lower surface of the lowermost one of the paper sheets and the upper surface of the paper sheet stacking plate.